This invention relates to a seat with a seating sensor, a seating detection device and an air bag apparatus in use for a vehicle such as an automobile.
In recent years, an air bag apparatus tends to be installed on the vehicle such as an automobile in order to protect a vehicle occupant in a crash condition. Such an air bag is normally contained within a steering wheel assembly or an instrument panel, and a squib or an inflator is ignited so as to inflate the air bag in a form of a balloon as the vehicle crash condition is sensed, whereby the occupant on the seat is protected from being forcefully and forwardly moved or inclined.
The air bag apparatus is also provided in the passenger""s side or assistant driver""s side as well as the driver""s side, and the passenger""s side air bag apparatus is adapted to be ignited and inflated at the same time of ignition and inflation of the driver""s side air bag apparatus, as the vehicle crash condition is detected. However, an occupant is not always seated on the passenger""s seat, and therefore, the passenger""s side air bag can be inflated regardless of presence or absence of an occupant, which may result in need of expense involved in somewhat meaningless repair works of the instrument panel.
In Japanese Utility-Model Publication No. 2519546, technical arrangement is proposed, which can detect presence or absence of an occupant with use of an ultrasonic distance-measuring device installed on an instrument panel. Further, another technical arrangement is proposed in Japanese Patent Laid-Open Publication No.1-160747, in which a sensing switch for detecting presence or absence of an occupant is installed inside a seat. Those arrangements might enable the air bag to be controlled in operation so that the passenger""s side air bag is not inflated when no occupant is seated on the passenger""s seat.
Although the conventional art of this technical field is capable of distinguishing presence or absence of a human or an object on the seat, it has the following defects;
(1) Recently, one type of accident raised a problem, in which a child or a physically small female person on a passenger""s seat was pressed by an inflated air bag. Occurrence of such an accident is considered to be resulted from inflation of the air bag which may be effected regardless of the physical condition of the occupant on the passenger""s seat. The prior art, however, cannot overcome the problem because the conventional arrangement is not so functioned that physical conditions of an occupant including height, weight and the like can be detected and that determination can be made so as to distinguish a child from adults.
(2) In the prior art, a determination cannot be made as to what is seated on the seat, i.e., whether a human is seated or whether an object is seated. Therefore, the air bag is normally operated in spite of an object being placed on the seat, which results in a somewhat wasteful expense involved in a replacement of the air bag, a repair work of the instrument panel, or a damage of the object due to the pressure of the air bag.
(3) In high-class cars, an automatic adjustment device may be installed, which includes a readable memory to be instructed with switching manipulation to output a preferable seat position, inclination of a seat back, position of a steering wheel and the like as desired by the occupant, thereby automatically regulating those devices or constituents to be desirable positions or angles. The prior art, however, is not capable of individually recognizing the occupant, and therefore, a plurality of users of the vehicle each has to input data of desirable seat position, seat back inclination angle, steering wheel position and the like into the memory to be memorized therein respectively, and in use, each user has to manipulate a registered switch or input a registered I.D. number or the like. Such manipulations of the device are somehow troublesome.
It is an object of the present invention to provide a vehicle seat with a seating sensor which is capable of calculating physical conditions of a subject on the seat, such as a height and weight of an occupant, determining whether the occupant is an adult or a child, determining whether the subject on the seat is a human or an object and individually recognizing an identification of the occupant.
It is another object of the present invention to provide a seating detection device which is able to determine whether a subject seated on the seat is a human or an object and which is capable of recognizing the physical figures of the subject when it is a human.
It is still another object to provide an air bag apparatus which is able to control an operation of the air bag in accordance with the physical figures of the occupant if the subject on the seat is a human, and which is capable of limiting the operation of the air bag if the subject is an object.
According to the present invention, the seat with seating sensor comprises a seating sensor provided on a seat back part for detecting a value and position of a pressure transmitted from a back of an occupant leaning against the seat back, and means for calculating a height of the occupant on the basis of the value and position of the pressure detected by said seating sensor.
Further, the seat with seating sensor according to the present invention comprises a seating sensor provided on a seat cushion part for detecting a value and position of a pressure transmitted from a hip of an occupant seated on the seat cushion part, and means for calculating a weight of the occupant on the basis of the value and position of the pressure detected by said seating sensor.
Still further, the seat with seating sensor comprises a first seating sensor provided on a seat back part for detecting a value and position of a pressure transmitted from a back of an occupant leaning against the seat back, a second seating sensor provided on a seat cushion part for detecting a value and position of a pressure transmitted from a hip of the occupant seated on the seat cushion part, and means for calculating a weight of the occupant on the basis of the value and position of the pressure detected by said first and second seating sensors.
Preferably, the seat with seating sensor further comprises means for comparing a resultant value obtained by the calculation of said calculating means with a predetermined reference value.
From another aspect of the present invention, the seat with seating sensor comprises a seating sensor provided on the seat for detecting a pressure transmitted from an occupant on the seat, memory means for storing data of the pressure of the occupant detected by said seating sensor, and means for comparing the pressure data currently detected by said seating sensor with the data memorized in said memory means and specifying the data closest to each other.
From still another aspect of the present invention, the seat with seating sensor comprises a seat body, a pad contained in the seat body, and a seating sensor interposed between a surface material of said seat body and said pad, wherein the seating sensor has a plurality of pressure sensitive sections for sensing a value and position of the pressure transmitted from an occupant, and wherein a protrusion in contact with said pressure sensitive section is provided on an upper surface of said pad.
Preferably, the above seating sensor includes a sensing element which is variable in electric resistance in response to the pressure.
It is preferable that the above seating sensor is provided with a plurality of sensing elements arranged in a formation of two-dimensional matrix.
The seating detection device according to the present invention comprises a hip sensor provided on a bench part of a vehicle seat, a foot sensor provided on a vehicle floor forward of said bench part, and subject determination means for determining what a subject is seated on the seat, based on the pressure detected by said hip sensor and said foot sensor.
From another aspect of the present invention, the seating detection device according to the present invention comprises a pressure sensitive sensor which is provided at least on a seat cushion part and which detects a pressure of a seated subject, and subject determination means for determining what the subject is, based on a variation with time on the pressure detected by said pressure sensitive sensor.
The subject determination means may be so arranged to compare the detected pressure value with a predetermined reference value, thereby determining whether the subject is a human or whether it is an object.
Alternatively, the subject determination means may be so arranged to compare the detected pressure value with a predetermined reference value, thereby determining whether the =subject is a human having a weight no less than a predetermined weight, or whether it is a human having a weight less than the predetermined weight.
The subject determination means also may be so arranged to compare the detected pressure value with a predetermined reference value, thereby determining whether the subject is a human or an object, and further whether the human has a weight no less than a predetermined weight or less than the predetermined weight.
Preferably, the seating detection device according to the present invention further comprises a sensing element which is variable in electric resistance in response to the pressure variation.
It is preferable that the seating detection device is provided with a plurality of sensing elements arranged in a formation of two-dimensional matrix.
The seating detection device of the present invention may include a sensor for detecting a temperature of the seated subject.
In the air bag apparatus according to the present invention, operation of the air bag is controlled on the basis of the results detected by said seating sensor provided in said seat.
Alternatively, the air bag apparatus of the present invention is controlled in its operation for the air bag on the basis of the results detected by said seating detection device.
From another aspect of the present invention, the air bag apparatus comprises a pressure sensitive sensor provided in the bench part of the seat, figure determination means for measuring a pressure distribution on the bench part through the pressure sensitive sensor and determining a physical figure of the occupant on the basis of a distance between two pressure peak points presenting beneath a hip of the occupant, and control means for controlling the operation of the air bag in accordance with the results of determination of the figure determination means.
Preferably, the above pressure sensitive sensor may include a sensing element which is variable in its electric resistance in response to the pressure variation.
It is preferable that the pressure sensitive sensor may have a plurality of sensing elements arranged in a two-dimensional matrix formation.